Chipper hammer



Nov. 6, 1962 v. B. BENNETT 3.06L863 CHIPPER HAMMER Filed Feb. 7, 1961VfR/VA!? a &BEN/VE rr INVENTOR 3,06l,863 Patented Nov. 6, 1962 hee3,061,863 CHIPPER HAMMER Vernard B. Bennett, 3800 Kings Way, Sacramento21, Calif. Filed Feb. 7, 1961, Ser. No. 87,693 4 Claims. (CI. 15--236)This invention relates to a chipper hammer. It relates more specificallyto such `a device for removing white painted marker lines from highwaypavements and grease or grime from the floor areas of bus sections,truck .terminals, garages or factory floors.

The chipper hammer according to the present invention was primarlydeveloped as the working tool for the Centrifugal Concrete Cleanerdescribed and illustrated in applicant's pending application, Serial No.57,293, filed on September 20, 1960. It is anticipated, however, that itwill also be capable of use as the working tool in other types ofmachines for the same purpose, and will have still other uses apart fromthat as a Component part of cleaning machines.

The construction of the chipper hammer according to the presentinvention presents a number of advantages over the chipper teeth in theCentrifugal Concrete Cleaner described and illustrated in the abovereferred to copending application. One of these is that the chipperteeth in the machine according to the co-pending application are made ofspring steel. As so made they perform their function in a satisfactorymanner but breakage occurs frequently. There are also other minordisadvantages of the chipper teeth so constructed. In the chipper hammeraccording to the present invention, the cutter tips are shorter and aremade of steel tubing, which has been case hardened.

Also in the Centrifugal Concrete Cleaner according to the above referredto co-pcnding application, the rotatable drum must be removed from themachine and dis-assembled in order to remove the chipper teeth forreplacement. In the chipper hammer according to the present invention,the cutter tips can be removed from the hammer without removing thelatter from the drums.

Further, in the Centrifugal Concrete Cleaner according to the abovereferred to co-pending application, there are two stop rods, the dogscarrying the chipper teeth restng against one stop rod on the idle arcof travel, above the horizontal diametral plane, and `abutting the otherstop rod on the working arc of travel, below the horizontal diametralplane. The chipper hammer accord- 'ing to the present invention is of Lshape and the drum has only one stop rod for each hammer, -one arm ofthe hammer abutting the stop rod on the idle arc of travel and the otherarm abutting same on the working arc of travel.

An object of the present invention is to provide a chipper hammer havinga cutter tip which is readily removable from the hammer itself.

Another object of the present invention is to provide a chipper hammerhaving a cutter tip of such shape as to leave the highway pavement fromwhich the painted marker has been removed, or the floor from which thegrease or grime has been removed, a plane and relatively smooth surface.

A further object of the present invention is to provide a chipper hammerhaving a removable cutter tip which can be hardened before use and whichis self-sharpening during operation.

Still other objects, advantages and improvements w'ill become iapparentfrom the following specification, taken in connection with theaccompanying drawings in which:

FIGURE 1 is a side elevational view showing the chip per hammeraccording to the present invention mounted between two parallelrotatable discs, with one of the discs being partially broken away, toshow the mounting of the chipper hammer.

FIG. 2 is a sectional view, taken on the section line 2-2 of FIG. 1 andlooking in the direction of the arrows, showing the working face of thecutter tip.

FIG. 3 is a sectional view, taken on the section line 3 3 of FIG. 1 andlooking in the direction of the arrows, showing the mounting providingfor chordal movement and partial swinging movement of the chipperhammer; and

FIG. 4 is a sectional view, taken on the section line 4-4 of FIG. 1 andlooking in the direction of the arrows, showing the mounting of thecutter tip on the chipper hammer.

Referring now to the drawings in detail and to FIG. 1 in particular,there are here shown at 10 and 12 two parallel discs, which are part ofthe rotatable drum of a centrifugal concrete cleaning machine. Thesediscs are mounted on a shaft 11 for rotaton therewith as the machinemoves over the surface being cleaned. The chipper hammer is designatedgenerally at 15 and is mounted between the discs 10 and 12 for limitedswinging movement and also for limited translatory movement radially ofthe discs. It will be understood that there are a plurality of thechipper hammers 15 (prefer ably at least six (6)) equally spacedarcuately of the discs 10 and 12, but only one is here illustrated anddescribed. In the construction of the rotatable drum according to myco-pending application, Serial No. 57,293, six of the chipper hammersare employed, between each pair of discs. As also described in theco-pending application, the rotatable drum will be comprised lengthwiseby any number, up to twent'yfour (24), of the parallel discs 10 and 12with the chipper hammers 15 mounted therebetween for the describedswinging and translatory movement.

Each chipper hammer has two arms lSa and lSb, at approximately rightangles. In the position shown in FIG. 1, the arm isa abuts a stop rod13, which is secured in aligned holes in the discs 10 and 12. On a lineapproximately bisecting the angle between 15a and 15b, the chipperhammer is formed with an elongated slot 16 having semi-circular ends. Inthis slot there is received a rod 14, which also is secured in alignedholes in the discs 10 and 12.

The outer end of the arm 15b is of greater thickness at 15c than themain body portion and the cutter tip 18 is mounted in this enlarged end.This tip is formed from a piece of steel tubing having a solid endportion 18b. The tubing is placed in a semi-cylindn'cal recess in afemale swaging die and struck by a longitudinally aligned complementaryswaging die of lesser diameter and shorter length. In its final form thetubing to `the right of the vertical diametral plane, as Viewed in FIG.4, is positioned inwardly of and in concentric relationship with respectto the wall to the left of the vertical diametral plane. Since the maleswaging die is shorter than the complementary female swaging die, thecutter tip is left with a base 1811 thicker than its working end. Whenthe preceding step is carried out, the solid end portion 1817 is thenscrew threaded. The inner cylindrical threaded section 18b is receivedin a screw-threaded hole 17 formed in the arm 1517 of the chipper hammertransversely of the latter and is held in place by an "Allen set screw19, which is received in a suitable screw threaded hole positioned alongthe longitudinal center line of the arm 15b and ntersecting the hole 17.

In operation the drum, which is comprised by an aligned series of theparallel discs 10 and 12, rotates with the shaft 11 in the clockwisedirection, as shown by the arrow in FIG. 1. For removing the paintedtraic lane marker lines from highway pavements, the rotatable drum willpreferably have eight (8) of the sets of chipper hammers betweenparallel discs 10 and 12 ranged axially of the shaft 11. Thisarrangement is suicient to remove a traffic lane marker line five incheswide from the highway pavement. This width can, of course, be increasedor decreased at the discretion of the manufacturer of the CentrfugalConcrete Cleaner.

The drum rotates with the shaft 11 in the clockwise direction, as shownby the arrow in FIG. 1. As the discs and 12 approach the position wherethe rod 14 is horizontally aligned with the shaft -11, as viewed in FIG.1, :the chipper hammer 15 is thrown outwardly and the arm 15a abuts thestop rod 13. When the cutter tip strikes the surface from which paint,grease or grimc is being removed, the chipper hammer 15 moves slghtlyupwardly, the slot 16 in the latter sliding along the pivot rod 14.

The shape of the cutter tip 18, as shown in FIGS. 2 and 4, that is thedouble semi-circular, concentric cutting edges is a very importantfeature of the present invention. If the cutter tip would be left in itsoriginal round or perfect circular shape, it would remove large circularor flat ring-shaped portions of material from the surface being cleaned,leaving the surface rough and irregular. By making the cutter tip 18 inthe shape shown, it removes a smaller portion of material and 'leavesthe surface more regular and smooth.

Upon rebound of the cutter tip 18 from contact with the surface beingcleaned, the chipper hammer 15 swings in the counter-clockwisedirection, the arms 15a moving away from the stop rod 13 and theenlarged head portion 150 striking this stop rod. After the cutter tipleaves the 'surface being cleaned, the force of rebound -carries theenlarged head 15c 'away from the stop rod 13, and the arm lsa thenreturns into abutting position with respect to -the stop rod 13.

- As stated above the cutter tips 18 are case hardened and their lifeexpectancy far exceeds that of the chipper rods in the Centn'fugalConcrete Cleaner of the co-pending application. Also, the cutter tips 18are self sharpening when used to remove painted markings, grease orgri-me, from concrete surfaces, due to the abrasive action of suchsurfaces on the same.

Having now fully described my invention, what I claim `as new and usefuland desire to secure by Letters Patent of the United States is:

l. A rotatable drum for use in wheeled surface cleaning machines movableover a surface being cleaned comprising at least two arallel plates, apivot rod positioned between said plates adjacent the peripheries of thelatter, -a stop rod posi-tioned between said plates radially inwardly ofthe pivot rod and forwardly of same in the direction of rotation of thedrum, an L-shaped chipper hammer pivoted at its vertex on said pivot rodand having its arms adapted to selectively abut the stop rod, and `aremovable cutter tip Secured in one of said arms.

2. A rotatable drum for -use in wheeled surface cleaning machinesmovable over a surface being cleaned, comprsing at least two parallelplates, a pivot rod positioned between said plates iadjacent theperipheries of the latter, a stop rod postioned between said platesradially inwardly of the pivot rod and forwardly of same in thedirection of rotation of the drum, an L- shaped chipper hammer havingportions defining an elongated slot at its vertex slidably receiving thepivot rod and having its arms adapted to selectively about the stop rod,and a removable cutter tip mounted in one of said arms.

3. A chipper hammer of L-shaped configuration having portions definingan elongated slot position approximately along the line bsecting theangle between the arms, portions of one arm of said L-shaped hammerdefining a longitudinal bore theren, and a cutter tip removably mountedin said bore.

4. A chipper hammer of L-shaped configuration having an elongated slotpostioned approximately along the line bisecting the angle between thearms, one of said arms having a transversely postioned screw threadedbore therein adjacent its outer end and a longitudinally postioned screwthreaded hole in the outer end intersecting said transversely postionedscrew threaded bore, a cutter tip having its outer free end comprised byintegrally joined spaced apart concentric semi-circular wall portions.and its inner end screw threaded and received in said transverselypostioned screw .threaded bore and a set screw in said longitudinallypostioned hole securing said cutter :tip in place.

References Cited in the file of this patent UNITED STATES PATENTS1,649,147 Blyth ..-V Nov. 15, 1927 2,279,922 Kraner Apr.. 14, 19422,911,737 Arx Nov. 10, 1959 FOREIGN PATENTS' 5 54,790 Germany July 14,19 32

